Simply plug the sensor into the underside of the Superrollo GW240/245/250/255, and you're done! A light guide measures both the incoming sunlight and the twilight state in the evening. During intense sunlight, the roller shutter lowers to the sensor. In twilight mode, the command to lower the shutter is given when twilight is reached. The values for the desired sunlight or twilight state can be adjusted using adjustment screws and with the help of corresponding symbols on the device.